Press equipment

Abstract

To provide a press device that can appropriately correct a stop position of a slide.SOLUTION: A press device 1 comprises: an eccentric shaft 2 that rotates around a shaft to reciprocate a slide 4; a brake mechanism 9 that brakes rotation of the eccentric shaft 2 or releases the braking; a brake cylinder 11 that switches braking of the eccentric shaft 2 and releasing of the braking by the brake mechanism 9; detecting means 12 that detects information θ concerning a position of the slide 4; and a controller 13 that controls the brake cylinder 11 on the basis of the information θ concerning a position of the slide detected by the detecting means 12. The controller 13 repeatedly performs first correction processing for correcting the braking by the brake mechanism 9 in accordance with information v concerning a speed of the slide 4 at a time after the slide 4 is pressed against an object W to be formed, and when continuous shift of a stop position of the slide 4 occurs, performs second correction processing for correcting the braking by the brake mechanism 9 in accordance with the continuous shift of the stop position of the slide 4.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a press apparatus. [Background technology]

[0002] For example, when a workpiece formed in a press is transported to the next process using a conveyor, robot, or the like, the press start angle timing is usually designed based on stopping the ascent of the slide at its top dead center and starting the descent of the slide from the top dead center. In this case, if the slide does not start descending from the top dead center, there will be a discrepancy between the timing at which the workpiece is pressed and the timing at which the conveying device conveys the workpiece, which could result in interference between the conveying device and the slide.

[0003] For this reason, various control devices and control methods have been developed to stop the slide at the top dead center when one stroke of the slide (i.e., the stroke in which the slide descends, presses (forms) the workpiece near the bottom dead center, and then rises again to the top dead center) is completed (see, for example, Patent Documents 1 and 2, etc.). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-144494 [Patent Document 2] Japanese Patent Application Laid-Open No. 2011-36876 Summary of the Invention [Problem to be solved by the invention]

[0005] By the way, when one stroke (i.e. the stroke in which the slide descends from top dead center to bottom dead center and then ascends to top dead center again) is completed, there are mainly two ways in which the slide does not stop at top dead center and the stopping position deviates from top dead center. In other words, due to factors such as the load energy required to press the workpiece near the bottom dead center differing for each workpiece, the amount of deviation (deviation angle) of the stopping position of the slide from the top dead center for each stroke may vary for each stroke (i.e., for each workpiece).

[0006] On the other hand, due to wear of the brake lining used to stop the movement of the slide, the stopping position after one stroke of the slide may overrun (i.e., the slide may stop beyond the top dead center) in several consecutive strokes. This phenomenon can occur not only due to deterioration over time such as wear of the brake lining, but also due to a rise in the temperature of the brakes when starting to drive (see Patent Document 2).

[0007] In addition to overrun, underrun (i.e., the phenomenon in which the slide stops before reaching the top dead center) may occur continuously over multiple strokes. In this specification, such a situation where the slide overruns or underruns occur continuously over multiple strokes will be expressed as "the slide stopping position is continuously shifted" or "the slide stopping position is continuously shifted", etc.

[0008] In addition, it is necessary to appropriately correct the stop position for each of the variations in the stop position of the slide for each stroke and the continuous deviation. However, during actual operation, the above-mentioned variation in the slide stopping position for each stroke and continuous deviation occur simultaneously each time the slide moves through one stroke, and therefore it is not necessarily easy to perform appropriate correction control for both types of deviation.

[0009] The present invention has been made in consideration of the above points, and an object of the present invention is to provide a press device that can appropriately correct the stop position of a slide. [Means for solving the problem]

[0010] The press device according to the present invention comprises: an eccentric shaft that rotates around an axis to reciprocate the slide; a brake mechanism that brakes or releases the brake on the rotation of the eccentric shaft; a brake cylinder that switches between braking and releasing the eccentric shaft of the brake mechanism; a detection means for detecting information regarding the position of the slide; a controller that controls the brake cylinder based on information about the position of the slide detected by the detection means; Equipped with The controller controls the amount of the slide after the slide is pressed against the molding object. rise A first correction process is repeatedly performed to correct the braking by the brake mechanism according to information regarding the speed, and when a continuous deviation occurs in the stopping position of the slide, a second correction process is performed to correct the braking by the brake mechanism according to the continuous deviation in the stopping position of the slide. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a press device that can appropriately correct the stop position of a slide. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a schematic diagram illustrating an example of the configuration of a press device according to a first embodiment. [Figure 2] 6 is a graph illustrating the timing of performing each process with respect to the rotation of the eccentric shaft in a normal operating state of the press machine. [Figure 3] 10 is a graph illustrating the occurrence of variations in the reference angle θa and the stop position of the slide for each stroke. [Figure 4] 10 is a graph illustrating a method of correcting for variations in the stop position of the slide for each stroke. [Figure 5] 10 is a table showing the relationship between the ascent speed of the slide and the amount of correction from the reference angle. [Figure 6]10 is a graph showing a state in which overrun continuously appears among continuous deviations in the stop position of the slide. [Figure 7] 10 is a graph showing a state in which underruns occur continuously among continuous deviations in the slide stopping position. [Figure 8] 10 is a graph illustrating a method of correction when overrun occurs continuously at the stop position of the slide. [Figure 9] 10 is a graph illustrating a method of correction when underrun appears consecutively at the stop position of the slide. [Figure 10] FIG. 10 is a diagram showing an example of a map of a braking start angle used when the first correction process and the second correction process are performed simultaneously. [Figure 11] 10 is a flowchart illustrating an example of a specific flow of a correction process for a stop position of a slide according to the first embodiment. [Figure 12] 10 is a flowchart illustrating an example of a specific flow of the correction process for the stop position of the slide when the controller 13 performs the second correction process in priority to the first correction process. [Figure 13] FIG. 10 is a schematic view illustrating an example of the configuration of a press device according to a second embodiment. [Figure 14] 10 is a flowchart illustrating an example of a specific flow of a correction process for a stop position of a slide according to the second embodiment. [Figure 15] 10 is a table showing the relationship between an index related to a second correction process and braking pressure. DETAILED DESCRIPTION OF THE INVENTION

[0013] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a press device according to the present invention will be described with reference to the drawings. In the following description, the terms "upper side" and "upward direction" and "lower side" and "downward direction" are used in accordance with the up-down direction in the drawings, but the present invention is not limited to this. In addition, in the following description, a case will be described in which the predetermined stop position of the slide (i.e., the planned stop position of the slide) is the top dead center, but the predetermined stop position of the slide may be set (planned) at a position lower than the top dead center.

[0014] [First embodiment] FIG. 1 is a schematic diagram illustrating an example of the configuration of a press apparatus according to a first embodiment of the present invention. In this embodiment, the press device 1 includes an eccentric shaft 2 such as an eccentric shaft or a crankshaft, a connecting rod 3, a slide 4, an upper die 5, a bed 6, a lower die 7, a clutch mechanism 8, a brake mechanism 9, a clutch cylinder 10, a dry brake cylinder 11, a rotation angle sensor 12, a controller 13, and the like.

[0015] The eccentric shaft 2 is composed of an eccentric shaft, a crankshaft, or the like, and is rotatably supported by the crown via a bearing (not shown). The connecting rod 3 connects the eccentric shaft 2 to the connecting portion 41 at the top of the slide 4, and converts the rotational movement of the eccentric shaft 2 into vertical translational movement of the slide 4, thereby raising and lowering the slide 4. In this way, the eccentric shaft 2 rotates around its axis, causing the slide 4 to reciprocate up and down via the connecting rod 3.

[0016] An upper mold 5 is fixed to the lower surface of the slide 4. A bed 6 is disposed below the slide 4, and a lower mold 7 is fixed to the upper surface of the bed 6. When the slide 4 descends, the workpiece W is sandwiched between the upper die 5 and the lower die 7, and the slide 4 is further lowered to the bottom dead point to pressurize and mold the workpiece W. After pressing the workpiece W, the slide 4 begins to rise and reaches the top dead point.

[0017] Although not shown, a transport device such as a conveyor or a robot is disposed near the bed 6. Then, when molding is completed and the slide 4 has risen to the top dead center, the conveying device removes the molded workpiece W from the lower die 7 and conveys it to the next process, or carries in the next molded workpiece W and sets it in the lower die 7.

[0018] On the other hand, although not shown, an external drive source such as a flywheel for rotating the eccentric shaft 2 around its axis is provided on one axial end side of the eccentric shaft 2 . A clutch mechanism 8 for connecting or disconnecting the eccentric shaft 2 to or from an external drive source, and a brake mechanism 9 for braking or releasing the rotation of the eccentric shaft 2 are provided on one axial end side of the eccentric shaft 2. Also provided are a clutch cylinder 10 for switching between connecting and disconnecting the clutch mechanism 8 to or from the eccentric shaft 2, and a brake cylinder 11 for switching between braking and releasing the brake mechanism 9 to or from the eccentric shaft 2.

[0019] Furthermore, a rotation angle sensor 12 is disposed on the other axial end side of the eccentric shaft 2 to detect a rotation angle θ (also referred to as a crank angle, etc.) of the eccentric shaft 2. The rotation angle sensor 12 may be disposed on the same end side as the clutch mechanism 8, and is not necessarily disposed at the end portion of the axial direction of the eccentric shaft 2. The rotation angle θ of the eccentric shaft 2 is set so that the angle when the slide 4 is at the top dead center is 0 degrees and the angle when the slide 4 is at the bottom dead center is 180 degrees. The rotation angle sensor 12 detects the rotation angle θ of the eccentric shaft 2 and transmits it to the controller 13.

[0020] If the rotation angle θ of the eccentric shaft 2 is known, the vertical position of the slide 4 (the position in the direction in which the slide 4 reciprocates) can be determined. Therefore, in this embodiment, the rotation angle sensor 12 functions as a detection means for detecting information regarding the position of the slide 4, and detects the rotation angle θ of the eccentric shaft 2 as information regarding the position of the slide 4.

[0021] The following describes the case where the slide 4 is configured in this manner, but instead of this configuration, it is also possible to configure the slide 4 so that the position and stroke amount are detected by a detection means such as an encoder or stroke sensor, and the detected position and stroke amount are used as information regarding the position of the slide 4. It is also possible to configure the control using the speed of the slide 4 and the rotation speed of the eccentric shaft 2. In this case, the speed of the slide 4 and the rotation speed of the eccentric shaft 2 can be detected by a detection means such as a sensor, and information regarding the position of the slide 4 can be calculated by, for example, integrating the detected speed of the slide 4 and the rotation speed of the eccentric shaft 2.

[0022] The controller 13 may be configured as a general-purpose computer equipped with a CPU (Central Processing Unit) or the like, or may be configured as a dedicated device. The controller 13 controls the clutch cylinder 10 and the brake cylinder 11 based on the information about the position of the slide 4 detected by the detection means.

[0023] In this embodiment, the controller 13 controls the clutch cylinder 10 and the brake cylinder 11 based on the rotation angle θ of the eccentric shaft 2 detected by the rotation angle sensor 12, causing the clutch cylinder 10 to connect or disconnect the clutch mechanism 8 to or from the eccentric shaft 2, and causing the brake cylinder 11 to brake or release the brake mechanism 9 to or from the eccentric shaft 2.

[0024] Hereinafter, each process performed by the controller 13 when the press machine 1 is in a normal operating state will be specifically described with reference to FIG. While the conveying device removes the molding object W and conveys it to the next process, the controller 13 controls the brake cylinder 11 to cause the brake mechanism 9 to brake the eccentric shaft 2, maintaining the slide 4 stopped at the top dead center (the rotation angle θ of the eccentric shaft 2 is 0 degrees).

[0025] It should be noted that "top dead center" when referring to "slide 4 stopping at top dead center" does not necessarily have to be exactly at top dead center (θ=0 degrees), but may be within an allowable range near top dead center (θ=0 degrees). Therefore, in the following, expressions such as "stop at top dead center" and "θ=0 degrees" will be used, but in these cases, "top dead center" and "θ=0 degrees" are concepts that include a predetermined allowable range in the vicinity.

[0026] The same applies when the predetermined stop position of the slide 4 is set (planned) to a position lower than the top dead center (θ=0 degrees). That is, for example, when the slide 4 is lowered from a position corresponding to θ=40 degrees, raised after passing the bottom dead center, and lowered after passing the top dead center to stop at a position corresponding to θ=40 degrees, i.e., when the predetermined stop position of the slide 4 is set at a position corresponding to θ=40 degrees, the predetermined stop position of the slide 4 includes a predetermined tolerance range in the vicinity of the position corresponding to θ=40 degrees.

[0027] Subsequently, when the next workpiece W is set in the lower die 7, the controller 13 controls the brake cylinder 11 to release the braking applied to the eccentric shaft 2 by the brake mechanism 9, and then controls the clutch cylinder 10 to connect the eccentric shaft 2 to the external drive source with a predetermined pressure by the clutch mechanism 8, thereby starting the rotation of the eccentric shaft 2. As a result, the slide 4 starts to descend from the top dead center. Then, the slide 4 reaches the bottom dead point (θ=180 degrees) in this state, and after the upper and lower dies press the molding workpiece W, it starts to rise toward the top dead point.

[0028] Next, when the rotation angle θ of the eccentric shaft 2 reaches a predetermined angle (see, for example, θ2 in the figure) while the slide 4 is rising, the controller 13 controls the clutch cylinder 10 to disconnect the external drive source from the eccentric shaft 2 via the clutch mechanism 8. Therefore, the eccentric shaft 2 continues to rotate by inertia, and the slide 4 rises accordingly.

[0029] Then, when the slide 4 rises further and the eccentric shaft 2 rotates further until the rotation angle θ reaches a predetermined angle (see, for example, θ3 in the figure), the brake cylinder 11 is controlled to cause the brake mechanism 9 to start braking the eccentric shaft 2, causing the eccentric shaft 2 to rotate with the brake applied. Hereinafter, this state will be expressed as the brake mechanism 9 starting to apply the brake to the eccentric shaft 2, etc.

[0030] In this state, the eccentric shaft 2 rotates while sliding against the brake lining of the brake mechanism 9, so the rotation speed of the eccentric shaft 2 decreases, and the ascending speed of the slide 4 decreases, until the slide 4 stops at the top dead center (θ = 0 degrees). In this way, one stroke of the slide 4 is completed.

[0031] [Regarding correction for deviations in the slide stopping position] As mentioned above, when the slide 4 completes one stroke, the slide may not stop at the top dead center, but may stop at a position that is shifted from the top dead center. The deviation can occur in two ways: (a) when the stopping position of the slide 4 varies for each stroke due to factors such as the load energy required to press the workpiece W being different for each workpiece W (variation between strokes), and (b) when the stopping position of the slide 4 varies for multiple strokes consecutively due to wear of the brake lining or the like (continuous deviation).

[0032] Therefore, in this embodiment, the controller 13 corrects the deviation of the stop position of the slide 4 in the following manner for each of the above two deviations of the stop position.

[0033] [Correction for variations in stopping position for each travel] As shown in Fig. 3, when the slide 4 is lowered to the bottom dead center and then rises without pressing (molding) the workpiece W (see A in the figure), if braking of the eccentric shaft 2 begins when the rotation angle θ of the eccentric shaft 2 reaches the above-mentioned angle θ3, the slide 4 will stop at the top dead center (θ = 0 degrees). Note that hereinafter, this angle θ3 will be referred to as the reference angle θa. In other words, the reference angle θa is determined in advance through experiments, etc., as an angle at which, when no pressure is applied to the workpiece W near the bottom dead center, braking of the eccentric shaft 2 is started at that angle θa, causing the rising slide 4 to stop at the top dead center.

[0034] However, when the workpiece W is pressed near the bottom dead center (see B in the figure), the energy required for pressing is released, and the rising speed v [spm] (strokes per minute: the number of times the slide moves back and forth per minute) of the slide 4 after pressing the workpiece W decreases compared to when pressing is not performed near the bottom dead center (see A in the figure). That is, the kinetic energy of the slide 4 in ascending direction decreases by the amount of energy required to press the workpiece W, and therefore, if braking of the eccentric shaft 2 is started when the rotation angle θ of the eccentric shaft 2 reaches the reference angle θa, the slide 4 will not be able to ascend to the top dead center and will stop at a position lower than the top dead center. In other words, an underrun state will occur.

[0035] Since the energy required to press the molding object W differs for each molding object W, the degree of underrun differs for each molding object W. Therefore, the degree of underrun (i.e., the stopping position of slide 4) varies for each stroke.

[0036] In this way, the variation in the stopping position of the slide 4 for each stroke occurs depending on the ascending speed v [spm] of the slide 4 when it ascends after being pressed against the molding workpiece W. Therefore, as a method of correcting for the variation in the stopping position of the slide 4 for each stroke (hereinafter, this correction process will be referred to as the first correction process), for example, the controller 13 can be configured to calculate the ascending speed v of the slide 4 at the time when the rotation angle θ of the eccentric shaft 2 detected by the rotation angle sensor 4 becomes a predetermined angle, and to control the brake cylinder 11 to vary the rotation angle θs at which the brake mechanism 9 starts braking the eccentric shaft 2 based on the calculated ascending speed v, thereby stopping the slide 4 at the top dead center.

[0037] It is also possible to use the above-mentioned "predetermined angle," that is, the rotation angle θ of the eccentric shaft 2 that triggers the controller 13 to calculate the ascending speed v [spm] of the slide 4, as the above-mentioned reference angle θa. In the following, we will explain the case where the ``predetermined angle'' is set to the reference angle θa, but it is also possible to configure the ``predetermined angle'' to be a rotation angle θ that is smaller than the reference angle θa (i.e., the position of slide 4 is lower than the position corresponding to the reference angle θa) and calculate the ascent speed v of slide 4.

[0038] The specific details will be explained below. In the following description, the rotation angle at which braking of the eccentric shaft 2 by the brake mechanism 9 actually starts is referred to as a braking start angle θs. When the workpiece W is not pressed (molded) (see A in Figure 3), the slide 4 will stop at the top dead center if the braking start angle θs is set to the reference angle θa, but when the workpiece W is pressed (see B in Figure 3), the slide 4 will stop at a position lower than the top dead center if the braking start angle θs is set to the reference angle θa.

[0039] Therefore, the controller 13 is configured to first calculate the angular velocity of the eccentric shaft 2 by differentiating the rotation angle θ of the eccentric shaft 2 input from the rotation angle sensor 4 at a predetermined cycle, and then calculate the ascending velocity v [spm] of the slide 4 at each cycle based on the calculated angular velocity. Then, as shown in FIG. 4, the relationship between the ascending speed v of the slide 4 calculated when the rotation angle θ of the eccentric shaft 2 detected by the rotation angle sensor 4 becomes the reference angle θa and the number of degrees by which the braking start angle θs should be delayed from the reference angle θa (i.e., the correction amount Δθ1 from the reference angle θa) so that the slide 4 stops at the top dead center is determined in advance.

[0040] The relationship between the ascending speed v [spm] of the slide 4 and the correction amount Δθ1 [degrees] is, for example, as shown in FIG. The above-mentioned "correction amount Δθ1 from the reference angle θa" corresponds to the correction amount for correcting the braking by the brake mechanism 9 in the first correction process. Also, Fig. 5 shows a case where the ascending speed v of the slide 4 in a no-load state, i.e., when no pressure is applied to the molding workpiece W (see A in Fig. 3), is set to 60 [spm].

[0041] Then, for each stroke, the controller 13 refers to the relationship in FIG. 5 and calculates a correction amount Δθ1 that indicates how many degrees the braking start angle θs should be delayed from the reference angle θa, based on the ascending speed v [spm] of the slide 4 at the time when the rotation angle θ of the eccentric shaft 2 reaches a predetermined angle (for example, the reference angle θa) as described above. In addition, when the ascending speed v of the slide 4 is within a certain range of the ascending speed v in Figure 5, it is possible to calculate the correction amount Δθ1 corresponding to the ascending speed v, for example, by interpolation (also called internal interpolation) processing.

[0042] Then, the controller 13 varies the braking start angle θs so as to delay it from the reference angle θa by the calculated correction amount Δθ1, and controls the brake cylinder 11 at the point when the rotation angle θ of the eccentric shaft 2 reaches the braking start angle θs, causing the brake mechanism 9 to start braking the eccentric shaft 2. Therefore, the slide 4 can be stopped at the top dead center (see FIG. 4). In this way, it is possible to configure the system so as to perform the first correction process, that is, correction for variations in the stop position of the slide 4 for each stroke.

[0043] [Correction for continuous deviation of stop position] On the other hand, as mentioned above, if the brake lining is worn or the temperature rises, the slide 4 may stop beyond the top dead center and overrun, as shown in Figure 6. In this case, the rotation angle θ of the eccentric shaft 2 increases from 180 degrees, and the slide 4 stops after it passes the top dead center (0 degrees).

[0044] Furthermore, if an abnormality or temperature drop occurs in the brake lining, the slide 4 may stop before reaching the top dead center (underrun). In this case, as shown in Figure 7, the rotation angle θ of the eccentric shaft 2 increases from 180 degrees, and the slide 4 stops before reaching the top dead center (0 degrees). In these cases, the deviation of the stop position of the slide 4 occurs continuously over multiple strokes.

[0045] Therefore, in the first correction process for the variation in the stopping position of the slide 4 for each stroke, the correction amount Δθ1 from the reference angle θa is calculated by focusing on the rising speed v [spm] of the slide 4, but in the correction for the continuous deviation of the stopping position of the slide 4 (hereinafter, this correction process will be referred to as the second correction process), it is possible to calculate the correction amount Δθ2 from the reference angle θa by focusing on the deviation amount of the stopping position of the slide 4 itself (i.e., the deviation amount of the rotation angle θ of the eccentric shaft 2 from 0 degrees (= 360 degrees) at the time the slide 4 stops). It should be noted that this "correction amount Δθ2 from the reference angle θa" corresponds to the correction amount for correcting the braking by the brake mechanism 9 in the second correction process.

[0046] Specifically, the controller 13 can be configured to determine that the slide 4 has overrun (the slide 4 has passed the top dead center and stopped) when the rotation angle θ of the eccentric shaft 2 exceeds 0 degrees (top dead center) by a predetermined angle or more and the slide 4 stops. Also, for example, if the slide 4 stops with the rotation angle θ of the eccentric shaft 2 smaller than a predetermined angle from 360 degrees (=0 degrees, top dead center), it is possible to configure it to determine that the slide 4 under-runs (the slide 4 stops before reaching top dead center).

[0047] As a method of performing the second correction process for continuous deviations in the stopping position of the slide 4 for each stroke, for example, the controller 13 can be configured to control the brake cylinder 11 to perform the second correction process when a predetermined number of consecutive strokes occur in which the slide 4 passes the top dead center and stops (overruns), or when a predetermined number of consecutive strokes occur in which the slide 4 stops before reaching the top dead center (underruns) (i.e., when continuous deviations occur in the stopping position of the slide 4).

[0048] In this case, for example, the predetermined number of times can be set to a fixed number such as three or five times. Furthermore, when an overrun or underrun occurs a predetermined number of times in succession as described above (i.e., when the stop position of the slide 4 is continuously shifted), the controller 13 can be configured to perform the second correction process by controlling the brake cylinder 11 to vary the braking start angle θs by a predetermined angle (for example, 10 degrees). That is, the correction amount Δθ2 of the braking start angle θs from the reference angle θa can be set to, for example, 10 degrees.

[0049] Then, when overrun occurs a predetermined number of times in succession, the braking start angle θs is reduced from the reference angle θa by the correction amount Δθ2, as shown in Fig. 8, and braking of the eccentric shaft 2 is started at an earlier point than the reference angle θa. As a result, the slide 4 comes to stop at (or near) the top dead center. Furthermore, if overrun occurs again a predetermined number of times in succession, it is possible to configure the device to correct the braking start angle θs so that it is further reduced by the correction amount Δθ2 from the current angle (i.e., in the above case, the angle that is smaller than the reference angle θa by the correction amount Δθ2).

[0050] Furthermore, if underrun occurs a predetermined number of times in succession, the braking start angle θs is increased from the reference angle θa by a correction amount Δθ2, and braking of the eccentric shaft 2 is started at a point later than the reference angle θa, as shown in Fig. 9. As a result, the slide 4 comes to stop at (or near) the top dead center. Furthermore, if underrunning occurs again a predetermined number of times in succession, it is possible to correct the braking start angle θs so that it is increased by a further correction amount Δθ2 from the current angle (i.e., in the above case, an angle that is larger than the reference angle θa by the correction amount Δθ2).

[0051] [Adjustment of the first and second correction processes (1)] Next, how to adjust the first correction process for the variation in the stop position of the slide 4 for each stroke and the second correction process for the continuous deviation in the stop position of the slide 4 will be described.

[0052] As described above, the variation in the stopping position of the slide 4 for each stroke occurs for each molding workpiece W, and therefore always occurs for each stroke. On the other hand, continuous deviation in the stopping position of the slide 4 usually occurs due to deterioration over time. Therefore, in normal cases, while the stopping position of the slide 4 varies for each stroke, a continuous deviation in the stopping position of the slide 4 begins to occur.

[0053] Therefore, the controller 13 is configured to repeatedly perform a first correction process to correct the braking by the brake mechanism 9 in accordance with information regarding the speed v of the slide 4 after the slide 4 is pressed against the molded object W, and to perform a second correction process to correct the braking by the brake mechanism 9 in accordance with the continuous deviation of the stopping position of the slide 4 when a continuous deviation occurs in the stopping position of the slide 4.

[0054] That is, the controller 13 performs a first correction process for the variation in the stopping position of the slide 4 for each stroke by changing the braking start angle θs at which the brake mechanism 9 starts braking the eccentric shaft 2 (the position of the slide 4 at which braking starts if control is based on the position of the slide 4) in accordance with information regarding the speed v of the slide 4 after the slide 4 is pressed against the workpiece W (in the above case, the rising speed v [spm] of the slide 4).

[0055] Since the braking start angle θs (or the position of the slide 4) determines the timing at which the brake mechanism 9 starts braking the eccentric shaft 2, it can also be said that in the first correction process, the control 13 is configured to correct the timing at which the brake mechanism 9 starts braking the eccentric shaft 2 in accordance with information about the speed v of the slide 4 after the slide 4 is pressed against the workpiece W. Furthermore, in this embodiment, while performing the first correction process in this manner, if a continuous deviation occurs in the stopping position of the slide 4, the controller 13 is configured to change the braking start angle θs (or the position of the slide 4) and perform a second correction process for the continuous deviation in the stopping position of the slide 4.

[0056] Specifically, the controller 13 can be configured to have a map of the braking start angle θs as shown in FIG. 10, for example. Figure 10 illustrates an example of a map of braking start angles θs in which the reference angle θa is 250 degrees, and braking start angles θs corrected in the first correction process by a correction amount Δθ1 (see Figure 5) corresponding to the rising speed v of the slide 4 are arranged along the vertical axis, and braking start angles θs corrected in the second correction process by a correction amount Δθ2 (e.g., 10 degrees) are arranged along the horizontal axis.

[0057] Then, for example, first, when the press machine 1 starts operating, the controller 13 sets the braking start angle θs to the reference angle θa, 250 degrees. Then, the ascent speed v of the slide 4 is calculated for each stroke as described above, and the braking start angle θs is calculated by vertically referencing the 250-degree column of the map of braking start angle θs (equivalent to calculating the correction amount Δθ1), thereby performing a first correction process for the variation in the stopping position of the slide 4 for each stroke.

[0058] Then, while performing the first correction process for each stroke in this manner, if a continuous deviation occurs in the stop position of the slide 4, the controller 13 shifts the column of the map to be referenced by one column in the horizontal direction. In this way, the second correction process can be performed to correct the continuous deviation of the stop position of the slide 4.

[0059] That is, if an overrun occurs consecutively, the column of the map to be referenced is shifted one column to the left, and if an underrun occurs consecutively, the column of the map to be referenced is shifted one column to the right. Then, by subsequently determining the braking start angle θs by referring to the shifted columns in the vertical direction, the first correction process for the variation in the stop position of the slide 4 for each stroke can be continuously performed.

[0060] The above process corresponds to calculating the overall correction amount Δθ when the first correction process and the second correction process are performed simultaneously by simply adding and subtracting the correction amount Δθ1 in the first correction process and the correction amount Δθ2 in the second correction process. That is, when overruns occur continuously, the overall correction amount Δθ is set as follows: Δθ=Δθ1-Δθ2 …(1) If underruns occur continuously, the overall correction amount Δθ is calculated as follows: Δθ=Δθ1+Δθ2 …(2) This is equivalent to calculating the

[0061] In this way, the controller 13 can be configured to perform a first correction process for variations in the stopping position of the slide 4 for each stroke, and, if a continuous deviation occurs in the stopping position of the slide 4, to perform a second correction process for the continuous deviation in the stopping position of the slide 4.

[0062] [Slide stop position correction process flow] Here, a specific flow of the correction process for the stop position of the slide 4 in the case of the above-mentioned configuration will be described with reference to the flowchart of FIG.

[0063] When the press machine 1 starts operating, the controller 13 sets m=0 (step S1). Then, the slide 4 descends from the stopped position (step S2), presses against the workpiece W near the bottom dead center, passes the bottom dead center (step S3), and starts to rise. As the controller 13 calculates the rising speed v [spm] of the slide 4 as described above for each period in which the rotation angle θ of the eccentric shaft 2 is input from the rotation angle sensor 4 (step S4).

[0064] Next, when the rotation angle θ of the eccentric shaft 2 reaches a predetermined angle (for example, a reference angle θa), the controller 13 calculates the correction amount Δθ1 corresponding to the ascent speed v [spm] of the slide 4 at that time by referring to the relationship in FIG. 5 (step S5). and, Δθ=Δθ1+Δθ2×m …(3) is calculated to calculate the overall correction amount Δθ when the first correction process and the second correction process are performed simultaneously (step S6). At this point, m is 0 (see step S1).

[0065] Then, the calculated overall correction amount Δθ is added to the reference angle θa to calculate the braking start angle θs (step S7). If the controller 13 is provided with a map of the braking start angle θs illustrated in FIG. 10, the braking start angle θs corresponding to the ascending speed v of the slide 4 calculated at the time when the rotation angle θ of the eccentric shaft 2 reaches a predetermined angle (for example, a reference angle θa) in step S4 is calculated by referring to the map of the braking start angle θs.

[0066] Next, when the rotation angle θ of the eccentric shaft 2 detected by the rotation angle sensor 4 reaches the calculated braking start angle θs, the controller 13 controls the brake cylinder 11 to cause the brake mechanism 9 to start braking the eccentric shaft 2 (step S8). Then, after the eccentric shaft 2 has rotated to a certain extent, the slide 4 stops (step S9).

[0067] Next, the controller 13 determines whether or not the stop position of the slide 4 has exceeded the top dead center and an overrun has occurred based on the rotation angle θ of the eccentric shaft 2 detected by the rotation angle sensor 4 (step S10). If an overrun occurs (step S10; YES), it is determined whether or not the stroke in which the overrun occurred has continued a predetermined number of times (step S11).

[0068] If the number of strokes in which an overrun has occurred is not the predetermined number of times in succession (step S11; NO), the controller 13 returns to step S2 without performing the process of step S12. Moreover, if the stroke in which an overrun occurs occurs a predetermined number of times in succession (step S11; YES), the controller 13 decrements m (step S12) and returns to step S2.

[0069] When m is decremented, the number of times that overruns have occurred consecutively is reset to 0. In addition, even if the overrun occurs in a plurality of consecutive strokes, if the overrun does not occur consecutively for a predetermined number of times, or if an underrun occurs while an overrun occurs consecutively, the number of strokes in which an overrun occurs consecutively is reset to 0.

[0070] For example, if m is decremented when m is 0 in the above process, m becomes -1 (step S12). Therefore, in the process of step S6 in the next processing routine, Δθ=Δθ1+Δθ2×(-1) ∴Δθ=Δθ1-Δθ2 The following calculation is required:

[0071] Furthermore, if the stroke in which an overrun occurs occurs again a predetermined number of times in succession (step S11; YES), m is further decremented (step S12), so that m=-2. Therefore, in the processing of step S6 in the subsequent processing routine, Δθ=Δθ1+Δθ2×(-2) ∴Δθ=Δθ1-2×Δθ2 The following calculation is required:

[0072] On the other hand, if an overrun has not occurred in the determination process of step S10 (step S10; NO), the controller 13 determines whether or not an underrun has occurred because the stopping position of the slide 4 has not reached the top dead center, based on the rotation angle θ of the eccentric shaft 2 detected by the rotation angle sensor 4 (step S13). If an underrun occurs (step S13; YES), it is determined whether or not the stroke in which the underrun occurred has continued a predetermined number of times (step S14).

[0073] If the number of strokes in which an underrun has occurred is not the predetermined number of times in succession (step S14; NO), the controller 13 returns to step S2 without performing the process of step S15. If the number of strokes in which an underrun occurs is a predetermined number of times in succession (step S14; YES), m is incremented (step S15) and the process returns to step S2.

[0074] When m is incremented, the number of times that an underrun occurs consecutively is reset to 0. In addition, even if the underrun occurs in a plurality of consecutive strokes, if the underrun does not occur consecutively for a predetermined number of times or if an overrun occurs while an underrun occurs consecutively, the number of strokes in which an underrun occurs consecutively is reset to 0.

[0075] For example, in the above process, when m is incremented from 0, it becomes m=+1 (step S15). Therefore, in the process of step S6 in the next processing routine, Δθ=Δθ1+Δθ2×(+1) ∴Δθ=Δθ1+Δθ2 The following calculation is required:

[0076] After that, if the stroke in which underrun occurs occurs again a predetermined number of times in succession (step S14; YES), m is further incremented (step S15), so that m=+2. Therefore, in the processing of step S6 in the subsequent processing routine, Δθ=Δθ1+Δθ2×(+2) ∴Δθ=Δθ1+2×Δθ2 The following calculation is required:

[0077] In addition, if the controller 13 has a map of the braking start angle θs as shown in FIG. 10, the process of decrementing m when overruns occur consecutively (step S12) corresponds to shifting the column of the map to be referenced one column at a time to the left. Furthermore, the process of incrementing m when underruns occur consecutively (step S15) corresponds to shifting the columns of the map to be referenced one column at a time to the right.

[0078] By configuring as described above, the controller 13 can realize correction processing of the stopping position of the slide 4, such as performing a first correction processing for the variation in the stopping position of the slide 4 for each stroke, while performing a second correction processing for the continuous deviation of the stopping position of the slide 4. Furthermore, in the press device 1, even in a situation where the variation in the stopping position of the slide 4 for each stroke and continuous deviation occur simultaneously, it is possible to control the press device 1 so that both are appropriately corrected, thereby making it possible to appropriately correct the stopping position of the slide 4.

[0079] [Adjustment of the first and second correction processes (2)] The above describes a case in which the controller 13 performs a first correction process to address the variation in the stopping position of the slide 4 for each stroke, while performing a second correction process to address the continuous deviation in the stopping position of the slide 4, treating the first correction process and the second correction process as equivalent, so to speak, to perform the correction process for the stopping position of the slide 4. That is, when calculating the overall correction amount Δθ when the first correction process and the second correction process are performed simultaneously, the correction amount Δθ1 in the first correction process and the correction amount Δθ2 in the second correction process are simply added or subtracted, as shown in the above equations (1) to (3).

[0080] However, depending on the press device 1, it may be better to configure the second correction process to determine whether the stopping position of the slide 4 has been appropriately corrected by the second correction process in a state where it is not affected by the first correction process or where the effect of the first correction process is small. Therefore, in such a case, when a continuous deviation occurs in the stopping position of the slide 4 and the second correction process is performed, the controller 13 can be configured to perform the second correction process in priority to the first correction process.

[0081] In this case, for example, when performing the second correction process, the controller 13 can be configured to perform the second correction process in priority to the first correction process by adding a weighted value smaller than 1 to the correction value Δθ2 of the braking start angle θs calculated in the second correction process (the correction value for the parameter that determines the timing for starting braking on the eccentric shaft 2) to calculate the overall correction value Δθ.

[0082] This will be specifically described using the flowchart shown in FIG. In the following description, in the flowchart of FIG. 12, the same processes as those explained in the flowchart of FIG. 11 are denoted by the same step numbers as in the flowchart of FIG. 11, and explanations thereof will be omitted.

[0083] When the press machine 1 starts operating, the controller 13 sets m=0 (step S1), and also sets n=0 and f=0 (step S16). Then, by referring to the relationship in FIG. 5, the correction amount Δθ1 corresponding to the calculated ascent speed v [spm] of the slide 4 is calculated (step S5), and it is determined whether f=0 or not (step S17).

[0084] If f=0 (step S17; YES), the controller 13 performs the processes from step S6 onwards as described in the flowchart of FIG. Then, when an overrun occurs in a predetermined number of consecutive steps (step S11; YES) and n is decremented (step S12), or when an underrun occurs in a predetermined number of consecutive steps (step S14; YES) and n is incremented (step S15), f is set to 1 (steps S18, S19).

[0085] On the other hand, if f=0 is not true in step S17 (step S17; NO, that is, if f=1), the controller 13 uses the following formula instead of formula (3) in step S6: Δθ=Δθ1×n×0.1+Δθ2×m …(4) is calculated to calculate the overall correction amount Δθ (step S20).

[0086] Next, the controller 13 adds the calculated overall correction amount Δθ to the reference angle θa to calculate the braking start angle θs, similar to the flowchart of FIG. 10 (step S7). Then, n is incremented (step S21), and if n is not 9 (step S22; NO), each process from step S8 onwards is performed. Therefore, in the first process immediately after the second correction process (steps S12, S15), the weight of the correction amount Δθ1 calculated in the first correction process is 0 (n=0), and the weight of the correction amount Δθ1 (n×0.1) increases with each process.

[0087] Furthermore, if n=10 in the calculation process of step S20, this is the same as performing the calculation process of step S6, so there is no need to perform the calculation process of step S20 with n=10. Therefore, if n=9 (step S22; YES), the controller 13 resets n and f to 0 (step S23) to end the process of increasing the weight of the correction amount Δθ1.

[0088] By configuring as described above, when a continuous deviation occurs in the stopping position of the slide 4 and the second correction process is performed, the controller 13 can be configured to perform the second correction process in priority to the first correction process. Furthermore, in the press device 1, even in a situation where the variation in the stopping position of the slide 4 for each stroke and continuous deviation occur simultaneously, it is possible to control the press device 1 so that both are appropriately corrected, thereby making it possible to appropriately correct the stopping position of the slide 4.

[0089] In the above example, after the second correction process (steps S12 and S15) is performed, the weighting of the correction amount Δθ1 calculated in the first correction process is increased over 10 steps, but it does not have to be 10 steps. Furthermore, the method of increasing the weight of the correction amount Δθ1 may be a method other than the linear increase method described above.

[0090] [Adjustment of the first and second correction processes (3)] In order to more accurately determine whether or not to perform the second correction process, it is also possible to configure the system to determine whether an overrun or underrun has occurred at the stopping position of the slide 4 only when there is no load, i.e., when no pressure is being applied to the workpiece W, or when the state is very close to that (i.e., when the ascending speed v of the slide 4 after pressing against the workpiece W is approximately 60 [spm]), and to perform the second correction process when a predetermined number of consecutive strokes in which an overrun or underrun has occurred occur.

[0091] [Second embodiment] The processing in the first embodiment described above can be implemented whether the brake cylinder is a dry type or a wet type. However, if the brake cylinder is a wet type, the controller 13 can be configured to control the wet brake cylinder to change the braking pressure applied to the eccentric shaft 2 by the brake mechanism 9 when performing the second correction processing, thereby performing the second correction processing for continuous deviations in the stopping position of the slide 4.

[0092] The press device 1 configured in this manner will be described below. In the following description, the same members and devices as those in the first embodiment will be denoted by the same reference numerals as those in the first embodiment, and the description of these members and devices will be omitted. In addition, in the following description, as shown in FIG. 13, a wet clutch / brake cylinder 11 in which the brake cylinder and the clutch cylinder are integrated will be used. *However, as shown in FIG. 1, the brake cylinder and the clutch cylinder may be formed as separate bodies.

[0093] FIG. 13 is a schematic diagram illustrating an example of the configuration of a press apparatus according to the second embodiment of the present invention. In this case, clutch / brake cylinder 11 * is a wet clutch / brake cylinder, and a piston 11a is disposed inside the cylinder. One side of the internal space defined by the piston 11a is an oil chamber 11b that is sealed liquid-tight. A brake spring 11c is disposed on the other side of the internal space, and the brake spring 11c constantly urges the piston 11a toward the brake mechanism 9.

[0094] Clutch / Brake Cylinder 11 * Hydraulic oil is supplied to and discharged from the oil chamber 11b via a solenoid valve 21 for switching between supply and discharge from a hydraulic pressure source 20 and an oil passage 22. Reference numeral 23 denotes a tank. Also, the solenoid valve 21 and the clutch / brake cylinder 11 * A pressure sensor 24 is connected to the oil passage 22 between the clutch / brake cylinder 11 and the oil passage 22. * The oil pressure in the oil chamber 11 b is detected and transmitted to the controller 13 .

[0095] The solenoid valve 21 is connected to the controller 13 . The controller 13 controls the solenoid valve 21 to operate the clutch / brake cylinder 11. * By controlling the supply and discharge of hydraulic oil to the oil chamber 11b of the clutch / brake cylinder 11, * The oil pressure in the oil chamber 11b can be varied.

[0096] Clutch / Brake Cylinder 11 *When hydraulic oil is supplied to the oil chamber 11b, the oil pressure in the oil chamber 11b increases, and the piston 11a moves to the right in the figure against the bias of the brake spring 11c. As a result, the braking applied to the eccentric shaft 2 by the brake mechanism 9 is released. When hydraulic oil is further supplied to the oil chamber 11b to increase the oil pressure in the oil chamber 11b, the clutch mechanism 8 connects the eccentric shaft 2 to an external drive source (not shown), and the eccentric shaft 2 rotates.

[0097] Conversely, if the hydraulic oil is discharged from the oil chamber 11b in this state to lower the oil pressure in the oil chamber 11b, the piston 11a is urged by the brake spring 11c and moves to the left in the figure, and the connection between the eccentric shaft 2 and the external drive source in the clutch mechanism 8 is severed. When the hydraulic oil is further discharged from the oil chamber 11b, the piston 11a is biased by the brake spring 11c, and the rotation of the eccentric shaft 2 is braked by the brake mechanism 9.

[0098] The braking pressure p [MPa] applied to the eccentric shaft 2 by the brake mechanism 9 is * This corresponds to the difference between the pressing force of the brake spring 11c on the piston 11a in the oil chamber 11b and the oil pressure in the oil chamber 11b (detected by the pressure sensor 24). Therefore, by lowering the hydraulic pressure in the oil chamber 11b, the braking pressure p applied to the eccentric shaft 2 by the brake mechanism 9 can be increased.

[0099] In such a press machine 1, as described above, when performing the second correction process, the controller 13 * By controlling the brake cylinder to change the braking pressure applied to the eccentric shaft 2 by the brake mechanism 9, a second correction process can be performed for continuous deviations in the stop position of the slide 4. By configuring in this manner, similar to the first embodiment described above, it becomes possible to control the press apparatus 1 so that both variations in the stopping position of the slide 4 from stroke to stroke and continuous deviations occur simultaneously, and to appropriately correct both of these.

[0100] Hereinafter, a specific flow of the correction process for the stop position of the slide 4 in the case of the above-mentioned configuration will be described with reference to the flowchart of FIG. In the following description, in the flowchart of FIG. 14, the same processes as those explained in the flowchart of FIG. 11 are denoted by the same step numbers as in the flowchart of FIG. 11, and explanations thereof may be omitted.

[0101] In this embodiment, in the first correction process for the variation in the stopping position of the slide 4 for each stroke, the controller 13 calculates the ascent speed v [spm] of the slide 4 as in the first embodiment (step S4), and based on the calculated ascent speed v of the slide 4, refers to the relationship in Figure 5 and calculates the correction amount Δθ1 corresponding to that ascent speed v (step S5). In this embodiment, the controller 13 then adds the calculated correction amount Δθ1 to the reference angle θa to calculate the braking start angle θs (step S24). θs=θa+Δθ1 …(5)

[0102] On the other hand, in this embodiment, as described above, the controller 13 controls the clutch / brake cylinder 11. * The second correction process is performed by controlling the braking pressure p [MPa] applied to the eccentric shaft 2 by the brake mechanism 9. Therefore, the controller 13 has in advance a relationship between the above m (an index relating to the second correction process described above; see steps S1, S12, and S15) and the braking pressure p [MPa], as shown in FIG. 15, for example.

[0103] This relationship indicates that the smaller m is, the more likely it is that an overrun will occur at the stopping position of the slide 4 (see steps S10 to S12), so the braking pressure p [MPa] applied by the brake mechanism 9 to the eccentric shaft 2 is increased to prevent an overrun, and the larger m is, the more likely it is that an underrun will occur at the stopping position of the slide 4 (see steps S13 to S15, etc.), so the braking pressure p [MPa] applied by the brake mechanism 9 to the eccentric shaft 2 is decreased to prevent an underrun.

[0104] Then, the controller 13 refers to this relationship and calculates the braking pressure p [MPa] corresponding to the current m (step S25). Then, when the rotation angle θ of the eccentric shaft 2 detected by the rotation angle sensor 4 reaches the braking start angle θs calculated in step S24, the controller 13 controls the solenoid valve 21 to start the braking of the clutch / brake cylinder 11. * The hydraulic pressure in the oil chamber 11b is varied, and the braking pressure p [MPa] applied to the eccentric shaft 2 by the brake mechanism 9 is changed to the calculated braking pressure p, thereby braking the eccentric shaft 2.

[0105] In this embodiment, when performing the second correction process, the controller 13 controls the wet clutch / brake cylinder (brake cylinder) to change the braking pressure p applied to the eccentric shaft 2 by the brake mechanism 9, thereby enabling the controller 13 to be configured to perform the second correction process for the continuous deviation of the stopping position of the slide 4.

[0106] Furthermore, as shown in FIG. 14, after the eccentric shaft 2 has rotated to a certain extent and the slide 4 has stopped (step S9), each process can be configured in the same way as in the first embodiment. With this configuration, the controller 13 controls the clutch / brake cylinder 11 so as to change the braking pressure p applied to the eccentric shaft 2 by the brake mechanism 9 when a stroke in which the slide 4 passes the top dead center and stops (an overrun stroke) occurs a predetermined number of times in succession, or when a stroke in which the slide 4 stops before reaching the top dead center (an underrun stroke) occurs a predetermined number of times in succession.* It is possible to configure the device so that the second correction process is performed by controlling the above.

[0107] By configuring as described above, the controller 13 can realize correction processing of the stopping position of the slide 4 by performing a first correction processing for the variation in the stopping position of the slide 4 for each stroke, while performing a second correction processing for the continuous deviation of the stopping position of the slide 4. Furthermore, in the press device 1, even in a situation where the variation in the stopping position of the slide 4 for each stroke and continuous deviation occur simultaneously, it is possible to control the press device 1 so that both are appropriately corrected, thereby making it possible to appropriately correct the stopping position of the slide 4.

[0108] In this embodiment, as in the first embodiment, when a continuous deviation occurs in the stopping position of the slide 4 and the second correction process is performed, the controller 13 can be configured to perform the second correction process in priority to the first correction process. In this case, for example, when performing the second correction process, the controller 13 can be configured to perform the second correction process with relative priority over the first correction process by multiplying the correction amount Δθ1 from the reference angle θa calculated in the first correction process by a coefficient smaller than 1.

[0109] Specifically, although the flowchart is omitted, for example, in step S24 of the flowchart shown in FIG. 14, instead of calculating the braking start angle θs by adding the correction amount Δθ1 to the reference angle θa, it is possible to calculate the braking start angle θs by multiplying the correction amount Δθ1 by n×0.1 (n=0 to 9) and adding the result to the reference angle θa, as in the flowchart shown in FIG. 12. θs=θa+Δθ1×n×0.1 …(6)

[0110] With this configuration, when a continuous deviation occurs in the stop position of the slide 4 and the second correction process is performed, the controller 13 can be configured to perform the second correction process in priority to the first correction process. In addition, even in a situation where the stop position of the slide 4 varies with each stroke and there is a continuous deviation at the same time, the press device 1 can be controlled to appropriately correct both of these.

[0111] In this case too, in order to more accurately determine whether or not to perform the second correction process, it is possible to configure the system to determine whether an overrun or underrun has occurred at the stopping position of the slide 4 only when there is no load, i.e., when no pressure is being applied to the molded object W, or when the system is in a state very close to that (i.e., when the rising speed v of the slide 4 after pressure is approximately 60 [spm]), and to perform the second correction process when a predetermined number of consecutive strokes in which an overrun or underrun has occurred occur.

[0112] It goes without saying that the present invention is not limited to the above-described embodiments, and can be modified as appropriate without departing from the spirit of the present invention.

[0113] For example, in each of the above embodiments, the case where the press device 1 presses the workpiece W is described, but the present invention can also be applied to press devices that perform various press processes such as punching, bending, and squeezing. Furthermore, in each of the above embodiments, a method of correcting the braking start angle θs has been described as a specific example of the first correction process. However, it is also possible to use a method in which, for example, the elapsed time from passing bottom dead center to the start of braking is measured, the time is corrected by an amount equivalent to the correction amount, and braking is started when the corrected time has elapsed. [Explanation of symbols]

[0114] 1 Press equipment 2 eccentric shaft 4 slides 9 Brake mechanism 11 Brake cylinder 11 * Wet clutch / brake cylinder (brake cylinder) 12 Rotation angle sensor (detection means) 13 Controller n×0.1 coefficient p Braking pressure v Slide rising speed (information about the speed of the slide) Δθ1 correction amount (correction amount used to correct braking by the brake mechanism in the first correction process) Δθ2 correction amount (a predetermined amount of correction to correct the braking by the brake mechanism in the second correction process) θ Rotation angle (information about the slide position) θa Reference angle (predetermined position) θs Braking start angle (predetermined position)

Claims

1. an eccentric shaft that rotates around an axis to reciprocate the slide; a brake mechanism that brakes or releases the brake on the rotation of the eccentric shaft; a brake cylinder that switches between braking and releasing the eccentric shaft of the brake mechanism; a detection means for detecting information regarding the position of the slide; a controller that controls the brake cylinder based on information about the position of the slide detected by the detection means; Equipped with the controller repeatedly performs a first correction process to correct braking by the brake mechanism in accordance with information on the ascending speed of the slide after the slide is pressed against the workpiece, and when a continuous deviation occurs in the stop position of the slide, performs a second correction process to correct braking by the brake mechanism in accordance with the continuous deviation in the stop position of the slide.

2. 2. The press apparatus according to claim 1, wherein the controller corrects the timing at which the brake mechanism starts braking in accordance with the information in the first correction process.

3. 3. The press apparatus according to claim 1, wherein the controller performs the second correction process in preference to the first correction process when a continuous deviation occurs in the stop position of the slide.

4. 4. The press apparatus according to claim 3, wherein, when performing the second correction process, the controller calculates an overall correction amount by weighting the correction amount for correcting the braking by the brake mechanism in the second correction process with a weight smaller than 1 and adding the weighted correction amount to the correction amount for correcting the braking by the brake mechanism in the first correction process, so that the second correction process is performed with priority over the first correction process, and the weight increases with each stroke of the second correction process.

5. 5. The press apparatus according to claim 1, wherein the controller performs the second correction process when a stroke in which the slide passes a predetermined stop position and stops occurs a predetermined number of times in succession, or when a stroke in which the slide stops before reaching the predetermined stop position occurs a predetermined number of times in succession.

6. 6. The press apparatus according to claim 5, wherein the controller performs the second correction process by controlling the brake cylinder to vary an amount of correction for correcting braking by the brake mechanism by a predetermined amount in increments when a stroke in which the slide passes a predetermined stop position and stops occurs a predetermined number of times consecutively or when a stroke in which the slide stops before reaching the predetermined stop position occurs a predetermined number of times consecutively.

7. 5. The press apparatus according to claim 1, wherein, in the second correction process, the controller corrects braking by the brake mechanism by changing a braking pressure applied to the eccentric shaft by the brake mechanism in accordance with the continuous deviation of the stop position of the slide and a magnitude of an index that is incremented or decremented in the second correction process.

8. 8. The press apparatus according to claim 7, wherein the controller performs the second correction process by controlling the brake cylinder so as to change a braking pressure applied to the eccentric shaft by the brake mechanism when a stroke in which the slide passes a predetermined stop position and stops occurs a predetermined number of times consecutively, or when a stroke in which the slide stops before reaching the predetermined stop position occurs a predetermined number of times consecutively.

9. 9. The press apparatus according to claim 7, wherein, when performing the second correction process, the controller multiplies the correction amount used to correct the braking by the brake mechanism in the first correction process by a coefficient smaller than 1, thereby performing the second correction process with higher priority than the first correction process.

10. 10. The press apparatus according to claim 1, wherein, as the first correction process, the controller calculates information about a speed of the slide at a time when information about the position of the slide detected by the detection means reaches a predetermined position, and varies braking by the brake mechanism based on the calculated information about the speed of the slide.

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